Date of Award

1995

Degree Type

Thesis

Degree Name

M.A.

Department

Psychology

First Advisor

Rourke, Byron P.,

Keywords

Psychology, Clinical.

Rights

CC BY-NC-ND 4.0

Abstract

Neuropsychological test data from 134 patients diagnosed with probable Alzheimer's disease (AD) were studied, to investigate whether subgroups of patients with qualitatively distinct neuropsychological profiles could be identified. Three empirical classification approaches were undertaken in this regard: Q-type factor analysis, hierarchical agglomerative cluster analysis, and iterative partitioning (i.e., k-means). It was theorized that there may be different underlying pathways of neuropathological progression of AD, such that the brains of those with spared semantic knowledge or visual-spatial/constructional abilities are initially affected asymmetrically. Furthermore, an earlier proposed neuropsychological model of AD accounting for these variations in early clinical presentation is extended and presented, in which three "ideal types" of AD are described and testable predictions made in their regard. In addition, it is suggested that past research in this area can be explained in terms of the Goldberg-Costa model of hemispheric specialization. As expected, the current research consistently identified 3 neuropsychological subgroups across the various clustering methods. Subgroup 1, comprising approximately half of the sample, is marked by severe anomia accompanied by moderate to severe constructional dyspraxia. Individuals in subgroup 2 display relatively spared visual-perceptual/constructional functioning, in the face of severe anomia. Members of subgroup 3 exhibit intact naming and non-verbal reasoning, with moderate difficulty copying overlapping figures. The 3 subgroups do not differ with respect to age, age at onset, duration of illness, educational level obtained or Hamilton depression rating. Results are discussed in terms of the subgroup and stage model approaches to the conceptualization of AD, and the theoretical model proposed. (Abstract shortened by UMI.)Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .F57. Source: Masters Abstracts International, Volume: 34-02, page: 0878. Adviser: Byron P. Rourke. Thesis (M.A.)--University of Windsor (Canada), 1995.

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